Biodiversity Patterns Research Articles

Speciation across life and the origins of biodiversity patterns

Abstract Speciation is the original source of all species richness. Here, I address two questions: (i) what might typical speciation look like across life? and (ii) how has speciation led to the diversity of life we see today? What is ‘typical’ depends on the richness of different groups. In groups associated with host organisms (which may dominate numerically), the processes of co-speciation and host switching are crucial. Among free-living organisms, allopatric speciation, ecological divergence, and prezygotic isolation appear widely important. Yet, the processes by which species become allopatric (and initially split) remain highly unclear. Among macroscopic organisms, the processes underlying the speciation of cryptic insect lineages may predominate, and are briefly reviewed here. Analyses of diversification rates among clades can illuminate the factors that drive speciation and species richness, and I review the advantages and disadvantages of different methods for estimating diversification rates. Patterns of species richness among named clades are generally related to variation in diversification rates, and specific types of ecological variables seem to underlie variation in diversification rates at different scales. Nevertheless, many richness patterns are unrelated to diversification rates and may be related to the time available for speciation instead, including richness among regions, clades, and traits.

Discussion on the biodiversity protection planning methods based on urban–regional scale

<p>This paper explores the relationship between the spatial scale and biodiversity protection level and thinks that under the specifi c urban-region scale, landscape diversity is the key level to the macroscopic protection of biodiversity. Based on the systematicness and the otherness of urban–regional environment and the biologic fl ow and process, the protection pattern of biodiversity within urban–regional scale should be established. The author holds that seeking the “optimal landscape pattern”is one of the core missions of biodiversity protection planning. Based on that, the paper summarizes the two types of city space and their biodiversity planning and design in two ways: first, the”Urban-rural landscape pattern optimization approach”specific to the space of city matrix, which includes “agglomeration segregation”,”landscape”, “green infrastructure”, three models and five pattern optimization strategies; second, the “Nature reserve approach” specific to the space of natural matrix, which includes”reserve circle”and”protected area network”two modes and six reserve design principles.</p>

Impact of climate change on ecology and biodiversity of Africa- a review

The most diverse among all the eco-biosphere entities is the aquatic ecosystem. With their dynamic biodiversity, energy cycles, prey-predator interactions and seasonal patterns aquatic ecosystems are unique in the nature. They are the most influenced of all the others due to their gradual sensitivity by a small change in the climatic condition. The sensitivity can be linked with their response towards temperature and light influencing several abiotic parameters including water, rainfall, pH, dissolved oxygen. The behavior and ecology of biotic components largely depend upon these abiotic parameters; a slight change in which can alter the community dynamics, species composition and diversity of the entire system. Compared to natural causes of climate change, anthropogenic activities are more influential and long standing. Excess use of fossil fuels, use of plastic, confluence of industrial gases and effluents, deforestation are few such examples for the detioriating situation. Both lentic, and lotic among fresh water, the marine with all its components, the estuarine diversity and distribution of species are facing challenges to cope up large-scale stress due to convergence of landmass, destruction of forests including mangroves, over usage of pesticides and fertilizers, exploitation of aquatic products including fish and corals. Not only the aquatic ecology and species in but also the human population and the community which largely depends upon them, disturbed leading to poverty, unemployment, population displacement and conflicts for water and cultivation land. Africa with all its floral and faunal biodiversity, extended lakes with vivid climatic zones is not away from the impacts of climate change. Africa is facing many challenges despite all efforts although a less-contributor of greenhouse gases. To understand all these aspects at the global level especially in Africa, this review paper is prepared accumulating from various sources to apprehend the causes, dimensions and challenges faced by various aquatic ecosystems because of climate change.

The Diversity and Community Pattern of Liverworts on Sygera Mountain, Tibet

Elevation has been a cornerstone of biodiversity research, and changes in the environmental factors behind it influence biodiversity and community patterns. Exploring the potential reasons behind liverwort community patterns has been a matter of multiplied interest for ecologists. In the present study, we recorded the liverwort taxa of Sygera Mountain growing on decaying wood, trees, soil, and rocks along an elevational gradient from 3100 m to 4500 m using complex field surveys in 2017 and 2019; we investigated the effects of elevation and various climatic factors on the liverworts’ diversity and community composition. Furthermore, we used mixed effect modeling, NMDS, ANOSIM, and CCA to help us critically assess liverwort diversity with respect to environmental variables. The results of the study showed a bimodal variation in the richness of liverwort communities according to elevation, with peaks occurring at 3500 m and 4100 m, respectively. The variation in elevation was significant, with communities at 4300 m being associated with high mean diurnal range environments and those at 3100 m and 3300 m favoring areas of higher solar radiation and the precipitation of the wettest month. Among the climatic factors, the variation in the mean diurnal range was found to be the determinant of liverwort communities. The results suggest that the mean diurnal range plays a crucial role in the distribution and community structure formation of mountain liverwort. This study deepens our understanding of liverwort ecology and emphasizes the importance of climatic variables in determining liverwort community composition.

Resilience of tropical invertebrate community assembly processes to a gradient of land use intensity

Understanding how community assembly processes drive biodiversity patterns is a central goal of community ecology. While it is generally accepted that ecological communities are assembled by both stochastic and deterministic processes, quantifying their relative importance remains challenging. Few studies have investigated how the relative importance of stochastic and deterministic community assembly processes vary among taxa and along gradients of habitat degradation. Using data on 1645 arthropod species across seven taxonomic groups in Malaysian Borneo, we quantified the importance of ecological stochasticity and of a suite of community assembly processes across a gradient of logging intensity. The relationship between logging and community assembly varied depending on the specific combination of taxa and stochasticity metric used, but, in general, the processes that govern invertebrate community assembly were remarkably robust to changes in land use intensity.

Reconnoitre on ichthyofauna of Mahanadi River of India: shifting diversity down the river continuum and linking ecological traits with patterns in biodiversity.

Anthropogenic alterations have paramount impacts on the alpha and beta diversity of aquatic resources, and fishes are predominantly susceptible to such impacts. Mahanadi River, one of the major peninsular rivers of India, has abundant fish resources, which play a significant role in supporting the fishers' livelihoods. The exploratory study in the river conducted for three consecutive years recorded 148 species under 53 families. Cyprinids dominated the fish diversity with 41 species, followed by Bagrids (9) and Sciaenids (7). One hundred-one species under 29 families were reported from the freshwater stretch. With a total of 111 species reported under 48 families, the estuarine and tidal freshwater stretch was more speciose, due to marine migrant species which advent the estuarine and tidal freshwaters stretch for breeding and feeding purposes. Tikarpara, a conserved site within a sanctuary, was the most species-diverse as well as a species-even site. The study also recorded the extension of the distributional range of 3 fish species and also 4 exotic species from the river. The seasonal variations in diversity indicated that the deviations were not prominent in freshwater sites, whereas in tidal brackish water sites, species richness was relatively higher in post-monsoon, and species evenness was higher during monsoon. Taxonomic distinctness test showed that the average taxonomic distinctness was high for tidal estuarine locations as they harbour taxonomically distant fishes. The hierarchical clustering of sites showed the inordinate effect of river gradient and fragmentation on the fish community structure. Analyzing the key drivers of the assemblage structure of the entire river, salinity was the major deterministic factor, and within the freshwater stretch, the major influences were depth, transparency, and specific conductivity. The study concluded that, despite all of its ecological stresses, Mahanadi still supports rich fish diversity, yet there is a notable shift in the fish community structure. There is a need for integrating molecular and morphological tools for the taxonomic revision of many genera and species for proper in situ and ex situ conservation measures and to formulate future biodiversity management plans addressing to reduce the impacts of the ecological threats.

Anthropogenic effects of habitat modification on anuran species diversity in a swamp forest area, Kenya

AbstractAnuran species are some of the good environmental indicators of habitat quality and condition in ecosystems. This is due to their amphibious life modes and sensitivity to environmental change caused by rapid expansion of agricultural activities, advancement of forest destruction, climate change and emerging infectious diseases. Understanding their diversity and distribution patterns is crucial for the development and implementation of effective species and habitat conservation strategies. The study aimed at assessing and comparing anuran biodiversity and distribution patterns between a protected (North Nandi Forest Reserve) and a non‐protected area (Kingwal swamp) to provide additional baseline information, both being among the underexplored areas in Kenya. Data were gathered in both dry and wet seasons, between October 2022 and June 2023 by employing standard sampling techniques for anurans(Visual encounter and pitfall traps with a drift fence) to maximise detection. Three habitat types‐ farmland, intermediate land and forest were exploited. A total of 1649 individuals from 21 different species, belonging to nine different genera and nine different families were recorded. Ptychadenidae was the most abundant family from the recorded anurans, while Dicroglossidae, Arthroleptidae, Pyxicephalidae and Ranidae were the least. High biodiversity was observed in the forest habitat (Protected) and least in the farmland (non‐protected). The wet season had high species abundance, diversity and richness compared to the dry season. There was a significant difference (p < 0.05) in diversity between the habitats in wet season, but no significance difference during dry season (p > 0.05) except for forest and farmland (p < 0.05). There was a significant difference in species abundance between seasons (p < 0.05), and between habitats (p < 0.05) in all seasons except for farmland and intermediate (p > 0.05), as well as farmland and forest (p > 0.05) during the wet season. Habitat type and season had no influence (p > 0.05) on species richness. Anuran biodiversity is a function of habitat diversity and season, with the associated differences in microhabitat structure providing diverse niches and ways of exploring resources. The modest sampling indicates that Kingwal Swamp and North Nandi Forest Reserve are rich and support anuran species, and the differences in anuran biodiversity between the 3 habitats demonstrates that conservation efforts continue to be a priority.

Floristic Richness in a Mediterranean Hotspot: A Journey across Italy.

Species richness is a fundamental property of biodiversity patterns and is properly expressed by the species-area relationship (SAR), namely the increase in the number of species with the area. Here, we studied and explored the species-area relationship with respect to vascular plant species in Italy and compared vascular plant richness among Italian administrative regions. Concerning the entire vascular flora (native and alien), the best-performing formula is the Arrhenius' Power function: S = c Az. The constants of this function are c = 241.2 and z = 0.281. The best-performing formula concerning just native (c = 245.2 and z = 0.263) and alien (c = 10.1 and z = 0.404) richness is the Power function as well. The floristically richest Italian regions considering the entire flora are Liguria, Friuli Venezia Giulia, and Trentino-Alto Adige, which are also the regions that are richest in alien flora unfortunately. Regions of particular naturalistic interest are Abruzzo, Valle d'Aosta, and Molise, because only these three regions exhibit native floristic richness that is higher than expected, and this is coupled with an alien floristic richness that is lower than expected. On the contrary, four regions (Lombardia, Veneto, Toscana, and Emilia-Romagna) show potentially severe conservation problems due to biological invasions since they experience native floristic richness that is lower than expected, with an alien floristic richness that is higher than expected. This study offers for the first time the 'c' and 'z' constants specifically calibrated at the national level for Italian vascular flora. The availability of such constants allows the calculation of the number of expected species for a given area to be investigated, providing a robust starting hypothesis for floristic studies.

Trichoptera Life Stages Present Distinct Responses to Environmental Conditions in Amazonian Streams.

Biological communities have their biodiversity patterns affected by environmental, spatial, and biogeographic factors that vary from taxa to taxa, and often between life stages. This is especially true when there are differences in the habitat the species use in each of them. Individuals of the insect order Trichoptera are mostly aquatic in their larval stage and terrestrial in their adult stage, which may result in different behaviors and environmental requirements. Our goal was to evaluate the congruence between the larval and adult stages of Trichoptera in Amazonian streams regarding their abundance, richness, and assemblage composition. Additionally, we tried to identify the main environmental factors related to each life stage. For this, larvae and adults of Trichoptera were sampled in the same sites at 12 streams in the Caxiuanã National Forest, Parástate, Brazil. Adult assemblages had greater richness of genera and abundance of individuals than the larval ones, and there was no congruence in the genera composition between these life stages. Our results also showed that different environmental variables structured Trichoptera larvae and adults. Since the sampling of larvae and adults proved to be complementary in the studied streams, we advise that Trichoptera diversity surveys consider both life stages of these organisms.

Biodiversity patterns of cyanobacterial oligotypes in lakes and rivers: results of a large-scale metabarcoding survey in the Alpine region

In this work, we characterised the cyanobacterial communities in the plankton and littoral biofilm of 38 lakes and in the biofilm of 21 rivers in the Alps and surrounding subalpine regions by 16S rRNA gene metabarcoding. We found little overlap in the distribution of amplicon sequence variants (ASVs) between the three habitats and between water bodies. The differences were caused by environmental filtering acting on the selection of the most abundant ASVs and a high contribution of rare oligotypes. The differentiation of community and genotype composition from specific water bodies was explained to a significant extent by environmental variables and morphometry. The taxonomic consistency of ASVs classified under the same genus name was assessed by phylogenetic analyses performed on three representative dominant genera, namely Cyanobium, Tychonema and Planktothrix. The analyses revealed eco-evolutionary adaptations in lakes and rivers, including some evidence for a polyphyletic nature. Monitoring individual genotypes in relation to environmental conditions will be useful to define the ecological amplitude of these taxa. However, the persistence or ephemeral nature of some of the rarest and most unusual ASVs has remained unknown.

Applying regional climatic indicators to study plant diversity patterns in Inner Mongolia

Climate factors have a major influence on biodiversity patterns have often used their mean values to reflect the distribution of different organisms, reducing the faceted information of the study unit to point information, a situation that may affect the accuracy of the study results. However, there has been a lack of systematic and comprehensive discussion on regional climatic indicators and their selection. To address this, we evaluated plant distribution and meteorological data from 88 banners and counties in Inner Mongolia considering five regional climatic indicators that reflect the state of climate factors, heterogeneity, and total resources in each sampling unit. Additionally, we compared and analyzed the advantages of the regional climatic indicators over mean climate indicators to determine the dominant climate factors driving the diversity patterns of plant families, genera, and species. Our results showed that the regional climatic indicators were better than the mean values at reflecting the diversity patterns of plant families and genera. In Inner Mongolia, plant species diversity patterns were mainly influenced by total precipitation and temperature heterogeneity indicators; and concurrently, the correlation between plant family and genus diversity patterns and regional climatic indicators was also higher than the mean values. The extent to which climate explains the diversity patterns of plants increases with decreasing plant taxonomic rank. The results of this study expand the available selection and use of climate indicators in biodiversity research and deepen the understanding of the effects of climate on plant family diversity patterns in arid and semi-arid regions. Therefore, this study provides new perspectives for the rational selection and accurate use of climate or environmental indicators in biodiversity conservation and restoration research.

Predicting bird diversity through acoustic indices within the Atlantic Forest biodiversity hotspot

The increasing conversion of natural areas for anthropic land use has been a major cause of habitat loss, destabilizing ecosystems and leading to a biodiversity crisis. Passive acoustic sensors open the possibility of remotely sensing fauna on large spatial and temporal scales, improving our understanding of the current state of biodiversity and the effects of human influences. Acoustic indices have been widely used and tested in recent years, with an aim towards understanding the relationship between indices and the acoustic activity of several taxa in different types of environments. However, studies have shown divergent relationships between acoustic indices and the vocal activity of most soniferous taxa. A combination of indices has, in turn, been reported as a promising tool for representing biodiversity in different contexts. We used uni- and bivariate models to test different combinations of 8 common indices in relation to bird assemblage metrics. We recorded twenty-two study sites in Brazil’s Atlantic Forest and three different types of environments in each site (forest, pasture, and swamp). Our results showed that 1) the best acoustic indices for explaining bird richness, abundance, and diversity were Bioacoustic and Acoustic Complexity; 2) the type of environment (forest, pasture, and swamp) influenced the performance of acoustic indices in explaining bird biodiversity, with the highest score model (biggest R2 value) being a combination between Acoustic Diversity and Bioacoustic indices. Our results do support the use of acoustic indices in monitoring the acoustic activity of birds, but combining indices is encouraged since it provided the best results. However, given the divergence we found across environments, we recommend that sets of indices are tested to determine which of them best describe the biodiversity pattern models for a specific habitat. Based on our results, we propose that biodiversity patterns can be predicted through acoustic patterns. However, the level of confidence will depend on the acoustic index used and on focal taxa of interest (i.e., birds, amphibians, insects, and mammals).

Wild relatives of potato (Solanum L. sec. Petota) poorly sampled and unprotected in Colombia

AbstractWild potato relatives (Solanum L. sec. Petota) play a vital role in crop improvement, understanding crop evolution, and conserving potato diversity. However, these invaluable resources are often neglected and underutilized and are susceptible to threats such as climate change, urbanization, and agricultural expansion. Little is known about the diversity, conservation status, and distribution of wild potato species in Colombia. To address this gap, we assessed the conservation status of five wild potato relatives conserved in the ex situ Colombian Central Collection. Five species were analyzed for their spatial patterns of biodiversity, conservation status, and conservation gaps. Colombia was found to have six centers of species richness, four areas of endemism, and six biogeographical regions. Of the five native species, only one was classified as adequately conserved for ex situ conservation, while the other four were considered low priority. In contrast, for in situ conservation, three species showed high priority, one was classified as medium priority, and one as low priority. In light of these findings, we propose three conservation strategies: (1) conducting collection missions to increase accessions in the national germplasm bank, prioritizing high‐priority species; (2) identifying and protecting unprotected natural habitats and engaging stakeholders to enhance in situ conservation efforts; and (3) establishing regional community genebanks to ensure localized conservation efforts.

Comprehensive inventory of páramo birds and their habitat affinities in a conservation hotspot, the Macizo del Cajas Biosphere Reserve, southern Ecuador

The páramo ecosystem is a significant centre of Andean bird diversity with high concentrations of threatened species. The Macizo del Cajas Biosphere Reserve’s páramos are a district of the biogeographic páramo province of northern Andes and are therefore considered a conservation hotspot with representative bird diversity. To enhance regional conservation efforts, comprehensive inventories of bird species that occupy this páramo are required. We present an updated bird inventory for the páramos of Macizo del Cajas and included validated records from eBird and GBIF databases along with records from continuous monitoring across this páramo landscape for five years. We also provide notes on habitat affinity and important new, rare, restricted range, and threatened birds. We report 112 bird species within the reserve, including five endemics, and three globally and 12 nationally threatened species. Finally, we discuss the use of habitat affinities as indicators of biodiversity patterns in páramo to improve conservation tools for key habitats.

Facets of functional diversity support niche‐based explanations for Australian biodiversity gradients

AbstractAimThere is widespread support that species richness increases with the available energy of an ecosystem, but the mechanisms underlying this driver of biodiversity patterns remain elusive. We evaluated gradients of functional diversity to test whether the higher species richness of productive, structurally diverse environments is due to a greater range of niches being supported by the abiotic conditions present (environmental filtering), greater availability of biotic resource and habitat niches (more niches) or increasing functional similarity of species (niche packing).LocationAustralia.TaxonBirds and mammals.MethodsWe used structural equation modelling to evaluate the relative contributions of climatic harshness (actual evapotranspiration, AET) and the availability of resource (gross primary productivity, GPP) and habitat (tree height) niches on taxonomic richness and functional richness, dispersion and evenness. We performed parallel analyses within 15 bioclimatic zones and continentally to evaluate the scaling of biodiversity gradients and the shifting balance between niche‐based mechanisms along environmental gradients.ResultsAll continental diversity gradients were primarily associated with energy variables, but while species richness of both taxa and all functional diversity measures of bird assemblages increased with AET, mammal functional diversity was more strongly associated with GPP gradients. Results were more variable at the regional scale, but species richness gradients along tree height (birds and mammals) and GPP (mammals) within bioclimatic zones tended not to be paralleled by increases in functional richness or dispersion.Main ConclusionsThe niche‐based explanations of biodiversity gradients varied in importance with scale, position on environmental gradients and taxonomic group. At the continental extent, bird biodiversity gradients were structured by environmental filtering by climatic harshness, while mammal biodiversity was related to the increasing availability of resource niches with increasing productivity. Niche packing was more prominent at the regional scale, especially in bioclimatic zones where productivity and vegetation height were less limiting, and in mammal assemblages, suggesting that biodiversity patterns scale differently for birds and mammals.

Influence of Ecological Multiparameters on Facets of β-Diversity of Freshwater Plankton Ciliates.

Understanding the relative importance of the factors that drive global patterns of biodiversity is among the major topics of ecological and biogeographic research. In freshwater bodies, spatial, temporal, abiotic, and biotic factors are important structurers of these ecosystems and can trigger distinct responses according to the facet of biodiversity considered. The objective was to evaluate how different facets of β-diversity (taxonomic, functional, and phylogenetic) based on data from the planktonic ciliate community of a Neotropical floodplain, are influenced by temporal, spatial, abiotic, and biotic factors. The research was conducted in the upper Paraná River floodplain between the years 2010 and 2020 in different water bodies. All predictors showed significant importance on the facets of β-diversity, except the abiotic predictors on species composition data, for the taxonomic facet. The functional and phylogenetic facets were mostly influenced by abiotic, biotic, and spatial factors. For temporal predictors, results showed influence on taxonomic (structure and composition data) and functional (structure data) facets. Also, a fraction of shared explanation between the temporal and abiotic components was observed for the distinct facets. Significant declines in β-diversity in continental ecosystems have been evidenced, especially those with drastic implications for ecosystemic services. Therefore, the preservation of a high level of diversity in water bodies, also involving phylogenetic and functional facets, should be a priority in conservation plans and goals, to ensure the maintenance of important ecological processes involving ciliates.

Global overview on groundwater fauna

AbstractGroundwater is an important global resource, providing water for irrigation, industry, geothermal uses and potable water. Moreover, groundwater contains the world's largest terrestrial freshwater biome with ecosystems, inhabited mainly by invertebrates (stygofauna) and microbes, undertaking important services including water purification, as well as nutrient and carbon cycling. Despite investigations on the spatial and temporal variations of groundwater fauna and the influence of environmental parameters on these organisms, in parts of the world, even the most basic knowledge of these ecosystems is still lacking. The aims of this study are to provide an overview on groundwater fauna (stygofauna) research, including the historical evolution of research topics and the development of sampling methods and secondly to identify the global distribution of groundwater fauna research and resulting data gaps. To achieve this, an extensive review of accessible groundwater fauna data was conducted by analysing 859 studies. It was evident that over time, there has been an exponential increase in the number of groundwater fauna studies together with changing paradigms in the research focus, particularly as sampling methods have developed from using simple nets, substrate samples and hand‐pumps in the beginning to recent molecular analyses (e.g. eDNA). As application of molecular methods becomes more common, knowledge on groundwater diversity and functional ecology is expected to increase. Studies on groundwater fauna are spatially uneven and are dominated by research in Europe and Australia, with few studies in Africa, Asia and the Americas. This presently biased view on groundwater biota hinders the identification of biodiversity patterns and ecosystem functions on a wider geographic and climatic scale. In the future, a more evenly distributed stygofauna sampling effort in currently underrepresented areas of the globe is necessary to ensure a more comprehensive perspective on stygofauna biodiversity, roles and functional significances. This is increasingly important with the accumulating knowledge of the sensitivities of these ecosystems to anthropogenic activities, including climate change, and is fundamental to effective management of these ecosystems.

How pondscapes function: connectivity matters for biodiversity even across small spatial scales in aquatic metacommunities

Habitat loss and fragmentation are growing global threats to natural habitats and their networks, posing significant challenges to biodiversity conservation. Globally, ponds are sharply declining in number because their small size makes them highly vulnerable to land use changes. While it is generally agreed that connectivity in habitat networks is crucial for sustaining biodiversity, the effect of connectivity on biodiversity patterns over small‐scaled habitat networks has so far received less attention given the general assumption that metacommunities lack spatial structuring on small scales. In this study, we tested whether this holds for multiple passively and actively dispersing organism groups in a well‐delineated pond metacommunity of 54 bomb crater ponds situated within 1 km. We investigated the influence of space and environment on species richness and metacommunity structure in these ponds, which share similar age, size, and shape and are subject to strong environmental gradients, making it an ideal study system. We specifically examined the impact of network centrality on taxonomic richness and eigenvector‐based spatial arrangement on metacommunity structure across different organism groups, including prokaryotes, microeukaryotes, zooplankton, macroinvertebrates, and amphibians. We found that while environmental filtering is the primary driver of community dynamics, there is also a significant spatial signal, particularly for passively dispersing groups, demonstrating the role of the central‐peripheral connectivity gradient. These findings highlight the importance of studying and protecting ponds as parts of a network rather than focusing on individual ponds.

Responses of taxonomic and functional diversity of soil mites to altitudinal changes in forest ecosystems of Lyuliang Mountains, Shanxi, China

The altitudinal gradient pattern of mountain biodiversity and its formation mechanism are hot topics in ecological research. The altitudinal variations of belowground invertebrates are less understood than aboveground plants and animals. With soil mites as the model soil animals, we investigated their distribution patterns from 1318 m to 2500 m above sea level in three mountains of Lyuliang Mountains based on species diversity and functional diversity. We used soil pH, total N, total P, total K, and organic matter content to identify potential drivers of soil mite communities and diversity along the altitudinal gradient. A total of 715 soil mites were collected, belonging to 3 orders, 27 families, 28 genera, and 29 species. Phthiracarus clemens, Geolaelaps praesternalis and Diapterobates humeralis were dominant mites. Non-metric multidimensional scaling showed that soil mites community composition varied significantly among different altitudes due to Epilohmannia ovata predominated in high altitude and P. clemens predominated in middle altitude. There were significant differences in individual density of soil mites among different altitudes. The Margalef, Shannon, and Simpson indices followed a unimodal distribution pattern along the altitudinal gradient. Functional richness and functional evenness showed a unimodal distribution pattern along the altitudinal gradient, while other functional diversity indices changed little with altitude. The RDA results indicated that total K and soil pH were the major drivers for the variations in soil mite communities. The Pielou index of soil mites was significantly positively correlated with soil pH, while functional evenness was negatively correlated with altitude. Individual density, species number, Margalef, Simpson and Shannon indices were significantly positively correlated with functional richness index. Species diversity and functional diversity of soil mites varied differently with altitude. In the future, we should strengthen long-term monitoring and dynamic functional properties of soil mites and the community assembly to deeply understand the relationship between biodiversity and ecosystem functions.

Biodiversity and genetic connectivity of Brachyura and Anomura (Decapoda) from artificial reefs in the Gulf of Mexico

Abstract Artificial reefs act as islands of biodiversity that provide substrate where sessile organisms can settle and mobile invertebrates and fishes can find shelter and food. Though these structures are common and widespread in the Gulf of Mexico, their community composition is not well understood. We aimed to ameliorate understanding of the invertebrate communities living on artificial reefs in the northeastern Gulf of Mexico by using molecular techniques and morphological examination to describe the biodiversity and genetic connectivity of crabs (Infraorders Anomura and Brachyura) living on and among artificial reefs near Pensacola, FL, USA. Specimens (N = 1,241) were collected from six artificial reefs using Autonomous Reef Monitoring Structures (ARMS) after four, six, and ten months of submergence, respectively, and were identified using DNA barcoding and morphological examination. Spatial and temporal trends in biodiversity were examined by comparing Hill-Shannon and Hill-Simpson diversities, richness, and canonical correspondence analysis. Population genetic analyses were performed on the two most commonly recovered species, Pseudomedaeus agassizii (A. Milne-Edwards, 1880) and Hexapanopeus paulensis (Rathbun, 1930). A total of 11 taxa were identified, and artificial reef shape was found to be influential in shaping spatial patterns of biodiversity. Species turnover was common across the ten months of sampling, and richness peaked at the ten-month mark. Population genetics revealed that there is high gene flow between the six sampling locations. This study is the first to describe the biodiversity of crab communities on artificial reefs in the northeastern Gulf of Mexico.